Second mount - recommendations

I own a CEM40. If you are looking for portability and good guiding for 8'' telescopes then look no further! My RASA8 with a dewshield usually gets around 0.30 - 0.50'' /px depending on the part of the sky I am shooting. It is probably the closest I have to something as long as a newtonian. In terms of portability I have to move it around the yard all the time (dang trees) and pack it up to go to dark sites. It is light enough to not be a huge hassle to do any of that.

I imagine the GEM45 would be a similar situation. Although, I find CEM designs to be slightly better than GEM designs. While HEM designs are cool, I think if you are looking for sub-arcsecond guiding then its best to stick with tried and true designs unless you want to spend the cash for a quality one.

This might sound counter-intuitive but perhaps you don't want a carbon fiber tube. A lighter newtonian will be more of a wind sail; more than a newtonian already is.

Hi, I hope you can help me a little.
As I move soon and finally have access to dark skies more readily again, I‘m thinking of getting a second mount besides my CEM25P. The plan is eventually to run two rigs simultaenously, as clear nights are rare here and I want to make the most of my time. Also planning to image with more aparture next year, and after contemplating, I‘d readily put a 6“ f/4 on my CEM25P and probably get good results (I imaged at 560mm and with the 2.4 microm pixels of my 183 mc pro before, guiding was good enough) but not the 8“ f/4 I desire…

It needs to fit following criteria:
- max cost 3000€
- mounthead not heavier than 8-9kg
- must carry an 8“ f/4 Newtonian (likely carbon tube)
- must be able to guide well enough for an image scale around 0.65 arcsec/pixel (planning to use my 183MC Pro with a 0.95 maxfield coma corrector on the 8“ f/4 Newtonian for galaxy imaging)

So far, I‘m torn between the CEM40, the GEM45, and those fancy new harmonious drive mounts (ZWO AM4, maybe the HEM27, the RST 135 is too expensive imo).

would any of those fit the bill? I mean if the CEM25P can handle imaging at 0.88“ / pixel, I kinda hope moving one class upwards and keeping the mobility, 0.65-0.7“ / pixel is doable…

If the CEM25P could handle that you'd be already in the image scale class that would be good for galaxy imaging. Somehow I doubt it, having its slightly larger brother, the GEM28.

While I think both the CEM40 or the GEM45 would fit the bill (maybe without much hassles or maybe not...), I'd personally chose the following:

https://www.teleskop-express.de/shop/product_info.php/info/p15180_Avalon-EVO-zero-GoTo-Mount.html

I had a look at that picture and came up with an average FWHM of between 5" and 6". With so large a FWHM it would be unwise to judge the quality of a mount and its tracking. This said I'm pretty sure that on good nights either of the iOptrons will do fine with a 8" f/4. I doubt, however, that imaging at your intended image scale of 0.65"/px is going to be much fruitful. I'd strive, if I were you, on a more conservative image scale, somewhere around the 1"/px. This will avoid disappointments in both the tracking performance (sub-freezing cold and possibly wind don't sit well with this kind of mounts, I know for experience) and in the imaging results.

Bob Lockwood:
Losmandy G11, these are what most of the guys I image with used before they all went to AP mounts. I use the AP 1200GTO and the Mach-1, have the 1100 on order.    G11, good and dependable mount.

The G11 is relatively heavy, much heavier than required from the OP and costs well over 3,000 euro in Europe. Besides that is so very old design.

Old means old. The design hasn't changed since, well, the '80s. Same weakness (large overhang for once) and same strengths. Does not enthuse. Even in the '90s we didn't regard it very much but then the offering was pretty restricted. Surprised is still churning out those mounts. More power to them if they still have a following. To me is just a non-starter with non-metric everything and DC motors. I'd rather take the chinese offerings or the european.

Hi, thanks for all the answers!

Regarding the FWHM in my NGC 2403 image: I didn‘t focus perfectly to begin with, and I never refocused - so this might be why the stars look absolutely horrible there - the newer images I did were also with my Asi 183MC Pro but at slightly reduced focal lenght - and the stars look nowhere this bad, but I also started using an EAF and set it to refocus every 1 Degree.
An imagescale of 0.88“ isn‘t gonna work nicely with a 80mm aparture anyways, but I didn‘t had the reducer back then, so I went ahead.
I still think a lower image scale is absolutely doable and what I crave - I‘m not sure how to go there though. For sure I need a better mount for this - the CEM25P might guide nicely with a small Apo on top (0.4-0.8“ RMS total is really really nice for that mount, depending on seeing and how close to the zenith I am - but a 4kg Apo and other stuff is well within the mounts limits) but if I want a bigger scope, I need to look elsewhere.

I pretty much crossed off the Harmonic drive mounts for now, but I saw that the CEM60EC is still in stock on a german vendor. I know, the current model is the CEM70, but with encoders it‘s too expensive, and an encoder mount with 27kg carrying capacity (mount head is a little over what I consider comfortable, but depending on my living situation aka how big the balcony is, this might work) for 3k € plus another 600€ for a Berlebach Planet might be a little over my planned budget to save up for, buuut this has way more room to grow than a CEM 40, EQ 6, and other mounts in the roughly 20kg class.
I don‘t know tho if the CEM60EC is still viable…


And yup, Losmandy G11, same as a CEM70EC is off the list, I really don‘t wanna cross the 4k area at all, preferably around 3k and have a mount that‘ll last me long - it‘s not like I‘m looking to put 14“ apartures on anything anytime soon, so I think there must be something suitable for a smaller image scale, that can carry 12-15kg photographic equipment nicely all while still being reasonably light. The EQ6-R Pro might be a steal at this pricepoint and is a good mount, but the mounthead is just insanely heavy, no option at all, also the basic tripod is not convincing for the given payload imo. the 12kg of the CEM60EC are a stretch, but as this is roughly what my CEM25P plus tripod brings on the plate, I know I can still carry this without swearing constantly… ;)